Brush-holder.



C. O. BERGSTROM.

BRUSH HOLDER.

APPLICATION FILED AUG. IZ. 1912.

1 ,150,486. Patented Aug. 17, 1915.

UNITED STATES PATENT OFFICE.

CARL O. BERGSTROM, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO B. F. STURTEVANT COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSSACHUSETTS.

BRUSH-HOLDER.

Application filed August 12, 1912.

T0 all whom it may concern.'

Be it known that I, CARL O. Bnnos'rnoiw, a citizen of the United States, residing at Boston, in the county of Suffolk and4 State of Massachusetts, have invented certain new and useful Improvements in 'Brush-Holders and I do hereby declare the following to be a full, clear, and eXact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to brush holders for electric motors or generators.

One object of the present invention is to produce a brush holderjvhich has provision for varying the size of its brush-receivingreeess so that -the same holdermay accommodate brushes of different sizes.

Another object of the present invention 'is to produce a brush holder in which most of the parts are of standard size but which is readily adapted for use on motors or generators offdifi'erent types and sizes by the substitution of a few simple parts in the brush holder.

Another object ofthe present invention is `to produce an improved tension device for the brushholder.

Still other objects of the present invention are to improve and simplify the certain details of construction of the brush holder hereinafter specifically described, the advantages of which will be apparent to those skilled in the art.

With the above objects in view, the present invention consists in a brush holder for electric motors or generators hereinafter described and particularly pointed out in the claims.

In the drawings which illustrate the preferred embodiment of the `present invention, Figure 1 is a side elevation of the brush holder; Fig. 2 is an elevation taken from the opposite side of the brush holder from Fig. 1; Fig. 3 is a sectional view along the line 8 -3 of Fig. 2 ;v Fig. 4 is a fragmentary sectional view along the same section as Fig. 3 showing a modification; Fig. 5 is a fragmentary side elevation similar to Fig. 1 showing a modification; and Fig. 6 is a view of the detent pin. y

Referring to the drawings, the brush holdercomprises two main members 2 and 4 which are preferably brass castings. The casting 2, which for convenience may be Specification of Letters Patent.

Patented Aug. 17, 1915.

Serial No. 714,617.

designated as the supporting block of the brush holder since upon it are mounted and supported the other parts of the brush holder, has two laterally extending ears 6 and 8 which are bored to receive a clamping screw 10 which has a part 12 of its shank tapered to engage and firmly grip the brush holder supporting bar 14 of the motor or generator. A flange 16 extends from the supporting block 2 across one side of the brush 18. The flange 16 has slots 20 therein to receive bolts 22 by means of which the second casting 4 is adjustably secured to the supporting block 2. A braided copper con` ductor 19 forms an electrical connection between the brush 18 and the supporting block 2. The second casting 4, which for `convenience may be designated as the tension bracket, is of a substantially U-shaped hori- Zontal cross section (Fig. 3), having two vears 24 and 26 through which is passed and riveted a steel stud 28. Loosely mounted to rotate on this stud is the hub 30 of the curved tension linger 32, the free end 84 of which bears against the top of the brush 18 t0 hold itagainst the commutator indicated at 36 (Fig. 1). Also loosely mounted to rotate on the stud 28 is a tension wheel 38. A helical spring 40 is connected between the hub of the tension finger 32 and the tension wheel 38. The spring 40 acts to exert a torque which presses the end ofthe tension finger 82 against the brush when the tension wheel 38 is turned. To hold the tension wheel 38 to maintain the tension on the spring 40, ratchet teeth 42 are formed on the side of the tension wheel 38. These ratchet teeth engage a detent or lock pin 44. The spring 40 not only exerts a torque tending to turn the tension finger 32, but also acts as a compression spring pressing against the tension wheel 38 -to hold the Y ratchet teeth 42 in engagement with the detent pin 44. The pin 44 has an eye 46 surrounding the stud 28 and the free end of the pin 44 is received in a small hole bored in the tension bracket 4 near the base of the ear 24. The insides of the ears 24 and 26 are milled or planed straight across to give them a finished surface. To form the detent by means of the pin 44 furnishes a cheaper and better construction than to inish the inside of the ear 24 so as to form the detent integral with it. Moreover, the

steel pin 44 forms a more durable detent than a projection from the brass casting 4. rlhe face of the wheel 38 inside of the ratchet teeth 42 is flat so that the ratchet teeth may be readily finished with a file. The eye of the pin 44 acts as a spacing washer to hold the hub of the wheel 38 away from the face of the ear 24 and so prevents the cramping of the wheel 3S upon the supporting stud, which would occur if only the ratchet teeth engaged the face of the ear 24.

The opposing faces and 52 of the two castings 2 and 4 are planed and form two of the side walls of the brush-receiving-recess, and the inside of the flange 16 is planed and forms a third wall of the brush-receiving-recess. The tension bracket 4 may be adjusted toward or from the supporting block 2 by means of the bolt and slot conand forms a third wall of the brush-receiving-recess may be varied to receive brushes of different thickness, the term thickness being used to designate the dimension of the brush which is at right angles to the faces 50 and 52. A lock plate 54 is mounted on the bolts 22. The corners of the lock plate are turned up as shown in Fig. 2 after the brush holder has been adjusted to prevent the vibration of the motor or generator from loosening the bolts 22. Brush guides G0 of different sizes may be secured to the supporting block 2 and the tension bracket 4 to accommodate brushes of different width, the term width being used to designate the dimension of the brush which is parallel to the faces 50 and 52. These brush guides 60, shown in Fig. 3, are of L- shaped cross section and are secured to the supporting block 2 and the tension bracket 4 respectively, by means of flatheaded screws 62 received through countesunk holes in the guide plates 60. The turned over edges of the guide plates project around the corners of the brush 18 and form guide surfaces opposite the flange 16. In Fig. 4, brush guides 60 of a larger size than those of Fig. 3, are shown so that a brush 18 of greater width can be received. Also, in Fig. 4, the supporting block 2 and the tension bracket 4 are shown spaced farther apart than in Fig. 3 so that a thicker brush 18 can be received.

The tension bracket 4 and the tension devices supported thereby constitute the greater number of parts of the brush holder. It is an advantage, therefore, to have these parts of a standard size and to use them on various sizes and types of motors or generators. In order that these parts of the brush holder may be of standard size for different sizes of motors or generators, the connection between the supporting block 2 and the tension bracket 4 is made so that supporting blocks of different sizes and shapes may be used interchangeably with the same tension bracket. In Fig. 5, a supporting block 2 is illustrated of a shape and size adapted to be mounted upon a larger supporting bar 14 than the supporting bar 14 shown in Fig. l. The flange 1G upon which the tension bracket is mounted is the same size and shape as the fiange 16 of the supporting block shown in Figs. 1 and 5. The brush engaging face of the supporting block 2, shown in Fig. 5, is of the same form as that of the supporting block 2, shown in Fig. l, so that the same set of brush guides 60 may be used with any supporting block. The brush holder of the present invention is, therefore, readily adaptable for use on motors or generators of different sizes and types. Vhen the brush holder is to be used upon a small motor or generator, a supporting block like that indicated by reference numeral 2 is assembled with the standard size tension bracket 4, and the supporting block 2 and tension bracket 4 are spaced comparatively near together to accommodate a small thickness brush, and a small set of brush guides 60 are used to accommodate a brush of small width. v When the brush holder is to be used with a motor or generator of largersize, a supporting block like that indicated by reference numeral 2 which has its ears 6 and 8 spaced to receive a larger supporting bar 14 is assembled with the same standard size tension bracket. For the larger generator with its larger brushes, the supporting block and tension bracket are spaced farther apart and a set of larger brush guides 60 is used. It is obvious that by standardizing the tension bracket and the parts of the tension device that the cost of manufacture of the brush holders for different sizes of motors can be reduced since the same standard parts can be used on different sized motors or generators.

While the preferred embodiment of theV present invention has been specifically illustrated and described, it will be understood that many changes may be made therein, and that the present invention is not limited to the illustrated embodiment, but may be embodied in other constructions within the scope of the invention as defined in the following claims 1. A brush holder for an electric motor or generator having, in combination, two members, one arranged to be mounted on the motor or generator and the second supported by the first member and carrying a tension device for the brush, said members having provision for supporting the second member in adjustable spaced relation to the first member to receive brushes of different sizes between them, for rigidly holding said members in adjusted spaced relation, substantially as described.

2. A brush holder for an electric motor or generator having, in combination, a plurality of elements forming a recess of substantially rectangular cross section to loosely receive the brush, and means for adjusting said elements relatively to each other to vary the size of the recess to accommodate brushes of different thickness and Width, and for rigidly holding said elements in adjusted spaced relation, substantially as described.

3. A brush holder for an electric motor or generator having, in combination, a plurality of elements forming a recess to loosely receive the brush, and means for adjusting said elements relatively to each other to vary the size of the recess to accommodate brushes of diil'erent sizes, and for rigidly holding said elements in adjusted spaced relation, substantially as described.

4. A brush holder for an electric motor or generator having, in combination, tWo members, one arranged to be mounted on the electric motor or generator, and the sec- -ond mounted on the iirst member to provide a brush-receiving-recess between them, and means comprising a slotted flange on one member projecting over the other member and a bolt passing through the slot in the iange and securedl to the other member for rigidly clamping the flange to the other member so that the tvvo members are rigidly held in adjusted spaced relation to accom-- modate brushes of dierent sizes, substantially as described.

5. A brush holder for an electric moto or generator having, in combination, tWo members spaced apart to hold the brush between them, one of said members having a flange extending across the other member and adjustably secured to the second member to hold the tivo members in adjusted spaced relation to accommodate brushes of di'erent thickness, and a brush guide engaging the side of the brush and removably mounted on one of said members to accomymodate brushes of different Width, substantially as described.

6. A brush holder for an electric motor or generator having, in combination, a brush holder body, a tension bracket mounted on the brush holder body and forming With it a brush-receivingrecess, a tension finger arranged to bear against the brush, a stud upon which the tension finger is pivotally mounted, a tension Wheel mounted upon said stud and having a ratchet connection with the tension bracket, and a helical spring surrounding thc stud and connected between the tension finger and tension Wheel exerting a torque to hold the tension linger against the brush and exerting a longitudinal pressure to hold the tension Wheel against its ratchet connection, substantially as described.

CARL o. BnnGsTRoM.

Witnesses:

GEORGE E. STEBBINS, MIRIAM CLEMENT.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents.

Washington, D. C.

It is hereby eertied'that in Letters Patent No. 1,150,486, granted August 17, 1915, upon the application of Carl O. Bergstrom, of Boston, Massachusetts, for an improvement in Brush-Holders, an error appears in the printed specification requiring Correction as follows: Page 2, line 19, strike outl the Words and forms a third Wall of and insert the syllables and Words nectton Q2 and Q0 so that; and

that the said Letters Iatent should be read with this correction therein that the same may conform to the record of the ease in the Patent Office.

Signed and sealed this 21st day of September, A. D., 1915.

[SEAL] J. T. NnWToN,

loting Commissioner of Patents.

It is hereby certified 'that in Letters Patent No. 1,150,486, granted August 17, 1915, upon the application of Carl O. Bergstrom, of Boston, Massachusetts, for an improvement in Brush-Holders, an error appears in the printed specification requiring correction as follows: Page 2, line 19, strike outv the Words and forms a third Wall of and insert the syllables and Words motion 22 and 2O so that; and

that the said Letters Patent should be read with this correction therein that the sarne may Conform to the record of the oase in the Patent Office.

Signed and sealed this 21st day of September, A. D., 1915.

J. T. NEWTGN,

cting Commissioner of Patents.

[SEAL] 

